Canon Kabushiki Kaisha

Toshimitsu Matsuu

Takeshi Uchida

Takeshi Yoshioka

Tatsuro Uchida

Kenji Yamagata

Yoshinobu Sekiguchi

A light source includes an upper electrode layer, a lower electrode layer, and an active layer interposed therebetween. At least one of the upper and lower electrode layers is divided into a plurality of electrodes separated from each other in an in-plane direction of the active layer. The separated electrodes independently inject current into a plurality of different regions in the active layer. The light source emits light by injecting current from the upper and lower electrode layers into the active layer, guide the light in the in-plane direction, and output the light. The plurality of different regions in the active layer include a first region not including a light exit end and a second region including the light exit end, and the second region is configured to emit light of at least first-order level. The active layer has an asymmetric multiple quantum well structure.

Light source and optical coherence tomography apparatus including the light source

A surface emitting laser includes a lower reflector, an active layer, a gap portion, an upper reflector, and a driving unit. The lower reflector, the active layer, the gap portion, and the upper reflector are arranged in that order. The surface emitting laser is capable of varying a wavelength of emitted light by changing a distance between the upper and lower reflectors. The driving unit moves one of the upper and lower reflectors in an optical axis direction of the emitted light. At least one of the upper and lower reflectors includes a stacked body in which first layers and second layers are alternately stacked, the second layers having a refractive index lower than a refractive index of the first layers, outermost layers of the stacked body being the first layers, and a third layer provided on at least one end of the stacked body.

Wavelength tunable surface emitting laser and optical coherence tomography apparatus including the same

A light source includes a control unit that controls currents injected into at least one light emitting region and a light emission spectrum conversion region. The at least one light emitting region includes a first light emitting region and a second light emitting region different from the first light emitting region, light that is emitted from the first light emitting region and passes through the light emission spectrum conversion region is combined with the light that is emitted from the first or second light emitting region and does not pass through the light emission spectrum conversion region. The control unit controls the currents injected into the light emission spectrum conversion region and the first light emitting region so that the current density of the light emission spectrum conversion region is smaller than the current density of the first light emitting region.

Light source and optical coherence tomography apparatus using the same

Provided is a vertical cavity surface emitting laser that includes a plurality of laminated semiconductor layers including an active layer and that oscillates at a wavelength &#x3bb;, wherein a resonator is formed by upper and lower multilayer reflecting mirrors has a structure that generates a longitudinal multimode, and the first active layer is arranged at a position shifted from a standing wave loop of the first longitudinal mode. According to the vertical cavity surface emitting laser capable of suppressing oscillation of the second longitudinal mode with a large gain and capable of single longitudinal mode oscillation based on the first longitudinal mode, the longitudinal mode spacing is narrowed by increasing the length of the resonator for single transverse mode oscillation at a high output, and the single longitudinal mode oscillation is possible even if longitudinal multimode oscillation occurs.

Growing community of inventors

Yokohama, Japan

Toshimitsu Matsuu